Well both these heads mate with the 1.4 block with no problem but it appears that the cut out (up at the top between the cam sprocket bearing caps) for the belt backplate in the X 16XE head is somewhat smaller than the cutout in the X 14XE head.
X 14XE (note how big the cut out is):
X 16XE:
Should I file away the head, cut the backplate up a bit or obtain an X 16XE backplate (this could be the hardest option).
X 14XE (note how big the cut out is):

X 16XE:

Should I file away the head, cut the backplate up a bit or obtain an X 16XE backplate (this could be the hardest option).